For humans its mugs and chocolate bars, for anthropoids its frozen fruit juice sticks and peanut butter

One of the seminal findings of behavioral economics is the endowment effect, in which humans show a tendency to value a good they have just come to possess more than the maximum price they would have paid immediately before they obtained it. Turns out the endowment effect may be a simian tendency too. (Ok, that’s all the appropriate synonyms we know, from now it’s chimpanzees.)